U.S. Pat. No. 3,854,583 (Amberg et al) discloses a container that includes a body which is fabricated from a sheet of an expanded thermoplastic material and which is provided with a rolled rim or bead at the mouth of such container. Such rolled rim or bead helps to stiffen the container at the mouth thereof, provides a smooth edge for drinking a beverage from the container, and provides a protrusion from the side wall of the container that is useful in securing a cap or closure to the container. Containers of the type illustrated in the aforesaid U.S. Pat. No. 3,854,583 have been extensively utilized as cups for single service quantities of a beverage, for example, coffee, and, when so utilized, the bodies of such containers have typically been manufactured in a nestable or frustoconical configuration from rectangular blanks of a heat-shrinkable thermoplastic material by a process which includes the shrinking of a cylindrical sleeve formed from such blank against the outer surface of a frustoconical forming mandrel. Typically, such cups have been produced by apparatus similar to that disclosed in U.S. Pat. No. 4,053,346 (Amberg et al), and may also be produced by apparatus similar to that disclosed in U.S. Pat. No. 4,072,549 (Amberg et al).
In U.S. applications Ser. No. 330,026 filed Apr. 14, 1989, and Ser. No. 504,168 filed Apr. 3, 1990, there are disclosed similar apparatus wherein the containers are formed in inverted position.
It has been known that such containers would be more stable if the bottom thereof were recessed. It has been suggested that such a recess can be formed in a method and apparatus wherein a foam sheet is first shrunk on a molding form, removed from the molding form and placed within a compression mold which is first heated and then cooled. See U.S. Pat. No. 3,967,991. Such a method, if successful, is costly and time consuming and requires costly and complex equipment.
Accordingly among the objectives of the present invention are to provide a two-piece nestable container which is formed from a double ended sheet that is first heat sealed to provide a sleeve like member and which container has a recess bottom; which container can be readily formed on known apparatus wherein the sheet is first heat sealed to form a sleeve and the sleeve is shrunk on a mandrel with minor modifications; wherein the method and apparatus does not adversely affect the normal forming method of containers without a recessed bottom; and wherein the construction of the recessed bottom provides stability to the container; wherein the container can be readily stacked; wherein the container has a sufficiently large recess to receive condiments such as coffee or tea and be nested for use in dispensing machines; and wherein the depth of the recess can relatively easily be changed.
In accordance with the invention, a two-piece nestable cup-like container comprises a side wall having an open upper end and includes a recessed bottom. This side wall is formed from a single double ended sheet of a heat-shrinkable thermoplastic material having an inner surface adapted to contact the liquid product to be contained in the container. The ends of the sheet are joined to one another along a liquid-tight seam. The side wall extends downwardly from a point near the open mouth of the upper end of the container to a point near the bottom and is thereafter folded at its lower edge upwardly to form a double wall portion and a radially upwardly extending annular portion that underlies a separate bottom member that is sealingly and joined to the radially inwardly extending portion of the bottom edge of the side wall. In accordance with the method and apparatus, a sleeve made from the sheet by joining the ends is heat shrunk on a mandrel and the free edge at the lower portion of the side wall is caused to shrink inwardly. Opposed shaping members are moved toward one another while the sheet is at an appropriate temperature for shrinking and forming to define the doubled wall edge and to heat seal tne bottom member to the radially inwardly extending portion.